Omnipolarization surface wave antenna



SEAHUH KUUM July 11, 1967 M. G. CHATELAIN 3,331,074

OMNIPOLARIZATION SURFACE WAVE ANTENNA Filed May 28, 1962 k, V m

Fug. 2

INVENTOR. MAURlCE G. CHATELAIN BY WBM United States Patent ,331,074 OMNIPOLARIZATION SURFACE WAVE ANTENNA Maurice G. Chatelain, San Diego, Calif., assignor to The Ryan Aeronautical Co., San Diego, Calif. Filed May 28, 1962, Ser. No. 198,257 Claims. (Cl. 343756) The present invention relates generally to antennas and more particularly to an omnipolarization surface wave antenna.

The primary object of this invention is to provide a surface wave type antenna sensitive to radiation with linear or circular polarization.

Another object of this invention is to provide a surface Wave antenna comprising a unitary structure in which the primary structural member serves as a ground plane and carries the entire antenna assembly.

' Another object of this invention is to provide an antenna which is compact, light in weight and has a minimum number of components.

Finally, it is an object to provide a surface wave antenna of the aforementioned character which is simple and convenient to manufacture and is adaptable to a variety of uses.

With these and other objects definitely in view, this invention consists in the novel construction, combination and arrangement of elements and portions, as will be hereinafter fully described in the specification, particularly pointed out in the claims, and illustrated in the drawing which forms a material part of this disclosure, and in which:

FIGURE 1 is a perspective view of the complete antenna;

FIGURE 2 is a sectional view taken on line 2-2 of FIGURE 1; and

FIGURE 3 is an enlarged sectional view of an alternative structure.

Referring now to FIGURES l and 2 of the drawings, the antenna is constructed entirely on a plate-like conductive ground plane 10, which can be sheet metal, a metallic portion of some other structure, or even plastic material with a metallic coating. Longitudinally disposed along the center of ground plane is a transmission line 12 comprising a linear array of spaced perpendicular monopoles 14. The first monopole in the transmission line 12 serves as a reflector 16, the second monopole being mounted in an insulated insert 18 in ground plane 10 and constituting a feed 20, the remainder of monopoles 14 acting as directors. Appropriate connections 22 and 24 are made to the feed 18 and ground plane 10, respectively, as in FIGURE 2.

Along each side of the transmission line 12 in spaced parallel relation thereto is a linear radiating array 26 comprising a plurality of substantially one quarter wavelength monopoles 28 spaced to form laterally aligned rows with the monopoles in the transmission line. The first monopoles in each radiating array 26, on either side of reflector 16, are perpendicular and serve as reflectors 30 for the respective arrays. The remainder of monopoles 28 in each array 26 are alternately inclined in opposite directions in perpendicular planes normal to the linear extent of the arrays, each laterally opposed pair of the two arrays being inclined in the same direction, so that one monopole 28 of each laterally opposed pair is inclined inwardly toward the respective monopole 14 while the other monopole 28 of that pair is inclined outwardly. All of the monopole elements except feed 20 can be directly secured to ground plane 10 in any suitable manner, forming an integral structure without loose or adjustable parts to become detached. The angle of inclination of monopoles 28 is preferably 45 degrees from the perpendicular 3,331,074 Patented July 11, 1967 for optimum omnipolarization sensitivity, but the angle can be varied to obtain specific radiation patterns.

The antennas can be considered as a central Yagi array for a transmission line, flanked by a pair of Yagi type radiating arrays, since each monopole, with its image on the other side of the ground plane, constitutes a halfwave resonant dipole.

With the monopoles 28 inclined in opposite directions, the radiating arrays 26 are excited by incident radiation of virtually any polarization and, in turn, excite the transmission line 12 from which feed 20 receives the signal. The radiation pattern can be varied somewhat by changing the number and spacing of the monopoles and bandwidth can be increased by increasing logarithmically the longitudinal spacing and length of the monopoles.

The antenna, being simple and light in weight, is particularly suitable for use in aircraft, missiles and space vehicles. Portions of the structural skin could be utilized as ground planes in such instances.

A particular example of the antenna suitable for use in or as a part of a space vehicle is illustrated in FIGURE 3, in which structural weight is reduced to an absolute minimum. In this configuration, the basic ground plane comprises a sheet of flexible plastic material 40 with a metallic conductive coating 42, the monopoles being hollow fingers 44 and 46 formed integrally with the ground plane material. The metallic coating is continued over fingers 44 to provide radiating monopoles 48, comparable to the monopoles 28 previously described. The feed 50 is insulated merely by leaving a gap between the metallic coating of the feed and the coating 42 on the ground plane. This structure can be folded compactly for delivery into space and erected by inflation or foam filling into a rigid antenna structure when required. Techniques for erection of such inflatable elements are well known and do not form a part of the present disclosure.

It is understood that minor variation from the form of the invention disclosed herein may be made without departure from the spirit and scope of the invention, and that the specification and drawing are to be considered as merely illustrative rather than limiting.

I claim:

1. An omnipolarization surface wave antenna, comprising:

a conductive ground plane;

a linear transmission line array of spaced conductive monopoles extending from said ground plane;

one of said monopoles being insulated from said ground plane and constituting a feed;

a linear array of spaced conductive radiating elements extending from said ground plane on each side of and substantially parallel to said transmission line array;

said radiating elements in each array being inclined alternately in opposite directions with the radiating elements in each laterally opposed pair being inclined in a common direction.

2. An omnipolarization surface wave antenna, comprising:

a conductive ground plane;

a linear transmission line array of spaced conductive monopoles extending perpendicularly from said ground plane;

one of said monopoles adjacent one end of the array being insulated from said ground plane and constituting a feed; 7

a linear array of spaced conductive radiating elements extending from said ground plane on each side of and substantially parallel to said transmission line array;

said radiating elements being in laterally opposed pairs with one of said monopoles therebetween;

the pairs of said radiating elements being alternately 3 inclined in opposite directions in perpendicular planes normal to the linear extent of the arrays.

3. An antenna according to claim 2 wherein said monopoles and said radiating elements are hollow and infiatable.

4. An antenna according to claim 2 wherein said radiating elements are inclined substantially at an angle of 45 degrees.

5. An omnipolarization surface wave antenna, comprising:

a conductive ground plane; 7

a linear transmission line array of spaced conductive monopoles extending perpendicularly from said ground plane;

one of said monopoles adjacent one end of the array being insulated from said ground plane and constituting a feed;

a linear array of spaced conductive radiating elements extending from said ground plane on each side of and substantially parallel to said transmission line array;

said radiating elements being in laterally opposed pairs with one of said monopoles therebetween;

the first of said radiating elements in each array at the end adjacent said feed being perpendicular and constituting reflectors;

the remaining pairs of said radiating elements being alternately inclined in opposite directions in perpendicular planes normal to the linear extent of the arrays.

References Cited UNITED STATES PATENTS 2,624,003 12/1952 Iarns 343-785 X 2,945,227 7/1960 Broussaud 343895 X 3,096,520 7/1963 Ehrenspeck 343824 X ELI LIBERMAN, Primary Examiner.

20 HERMAN KARL SAALBACH, Examiner. 

1. AN OMNIPOLARIZATION SURFACE WAVE ANTENNA, COMPRISING: A CONDUCTIVE GROUND PLANE; A LINEAR TRANSMISSION LINE ARRAY OF SPACED CONDUCTIVE MONOPOLES EXTENDING FROM SAID GROUND PLANE; ONE OF SAID MONOPOLES BEING INSULATED FROM SAID GROUND PLANE AND CONSTITUTING A FEED; A LINEAR ARRAY OF SPACED CONDUCTIVE RADIATING ELEMENTS EXTENDING FROM SAID GROUND PLANE ON EACH SIDE OF AND SUBSTANTIALLY PARALLEL TO SAID TRANSMISSION LINE ARRAY; SAID RADIATING ELEMENTS IN EACH ARRAY BEING INCLINED ALTERNATELY IN OPPOSITE DIRECTIONS WITH THE RADIATING ELEMENTS IN EACH LATERALLY OPPOSED PAIR BEING INCLINED IN A COMMON DIRECTION. 